Transport Advice Needed ⛴️🚙

Hello! quick qns:

1) ferry to zamami – is there a way to book online? I went to the website to see the schedule but couldn’t book anything. I read on reddit you need to call to book, I don’t have a Jap number so would prefer if I can book online!

2) How early must we get to the ferry to board?

3) car recs for Okinawa main island ? 4 pax, 3 cabin and 1 big luggage. We plan to drive all around the island.

4) Is there a rental company you recommend that I can pick up in Naha and return at Airport

Thanks in advance!! Planning this trip by myself (for myself + senior parents/aunt) is not as straightforward as id hoped hahaha

by Traditional_Bag9350